Computer users, in their daily course of activities, send electronic messages containing URL links to their friends, family and coworkers involving items of personal interest or work related subject matter. For instance, a user may send a particular URL link to someone they think might enjoy it via an email, instant message, or any other electronic messaging system. Furthermore, the URL link may contain data content such as a word document, a PDF document, a gif image or plain text.
Consider the following case when the contents of an intended URL link change after the message containing the URL has been sent. For example, suppose one co-worker sends a second co-worker an email containing a URL link pointing to an image that contains a joke that the sender finds funny. After the message has been sent, the contents of the pointed URL are modified by the site owner with inappropriate contents. When the receiver opens the email and clicks on the URL link, he/she finds the new contents offensive. There is a possibility that the relationship between the co-workers will be compromised. More damaging would be if the sender had sent the email to a distribution list, thereby offending many individuals inadvertently.